Anyway i can improve my team

delta venusuar item:idk what to give it. moves:energy ball psychic moon blast psycho boost delta gallade item : delta galladite. moves: drain punch thunder punch ice punch psycho cut
talonflame item : charcoal moves: brave bird flare blitz fly steel wing t-tar item:armor moves: earthquake stone edge dragon pulse crunch greninja item: expert belt moves: extrasensory night slash surf water shuriken grarchomp item:leftovers moves:dragon claw dragon rush dig sandstorm

If you want to keep all your members;

D. Venu: Switch out Psycho Boost and Energy Ball for Calm Mind and Moonlight. Psycho Boost works best for Mega D. Venu.

M. D. Gall: You could use Wild Charge/Icicle Crash for more power, but with recoil/lower accuracy. Switch out Psycho Cut for Ice Shard, you need priority and you already have the Psychic typing covered.

Talonflame: Ideally, find a better item. However, Charcoal’s okay for now. Remove Fly unless you really, really need the utility, as Pika Taxis are available in every city. Replace Fly with Roost, you have two STAB recoil moves, so Talonflame will appreciate it.

Arm. Tyranitar: Don’t bother with Dark Pulse, especially since you already have Crunch.You could breed for Dragon Dance, Iron Head, or Outrage. Barring that, relearn one of the Elemental Fangs.

Greninja: Assuming it is Protean, try to trade/breed an Ice Beam Protean Froakie, as having two water moves is very redundant on any Expert Belt Pokemon, especially with Protean.

Garchomp: I would seriously reconsider using Tyranitar and Garchomp. Right now, Garchomp has no edge over Armor Tyranitar. If you must use Garchomp, use a Sand Veil Garchomp,breed for Outrage and Earthquake, and just try to fill the rest with coverage I suppose.

just to ask which pokemon do u need to breed to greninja to get ice beam

You can use either Lapras (learning at 32), Dewgong (learning at 55), or oddly enough, Octillery (learning at 40).

ok thank you